Die or pressure casting machine for plastic masses



n 16, 1941. P. B'EYERLEIN' y* 2,265,995

DIE OR PRESSURE CASTING MACHINE FOR PLAS-TITO MASSES Filed April'ls.,1938 l zuena Pza/2 (yerlein Eg MSManQ@ Patented Dec. I6, 1941y UNI-T EDsfr-Aras f PATEN azcssss `orrlcr.

Application April 15, rasa, serai No. 202,287 In Germany April .23111937I 2 Claims. (Cl. 18-30) This invention relates to die or pressurecasting machines for plastic masses.

In die or pressure casting machines for plasti masses in order toprevent aconsiderable further quantity of the mass from iiowing out ofthe nozzleorificeafterthenozzlehas been separated from the mould, theresult of which would be to interfere with the proper operation of themachine, it-has previously been proposed to insert in the front part ofthe nozzle a closure member which is opened by a controllingdevicebefore the beginning of the extrusion process and is closed afterthe extrusion process is complete.

A closure of this type is considerably simplified by means of thepresent invention because the controlling device for the closure memberis eliminated.

In a construction in accordance with the invention, the nozzle ismounted in the nozzle head so as to be axially displaceable therein andis provided with transverse passages leading from the nozzle passage;when the cylinder containing the plastic mass is withdrawn, the. nozzleis held by a spring in a position in which the transverse passages areshut of! from the passage through which the mass is supplied and, whenthe nozzle is applied to the casting mould, the nozzle is moved into aposition in which the passage through which the mass is supplied isbrought into communication by way of the transverse passages with thenozzle orifice. The opening of the closure member at the correct timetherefore takes place automatically 'without the aid of a controllingdevice solely owing to the nozzle bearing against the mould and theclosing is eiected by the spring. The nozzle itself is constructed asthe closure member while the nozzle head acts as a casing in which thenozzle slides.

Preferably, as an additional safeguard, the nozzle is provided with astop which limits its stroke and hasA a seating surface which, when` thetransverse passages are in the closed position. bears against a seatingprovided on the l form oi' .construction ofthe iront end'of the cylindercontaining the plastic mass and the mould which coacts with it beforethe two` parts are brought into contact with one another.

Figure 2 is a view showing the positionsroi the BSS ures 1 and 2 theautomatic opening of the closure member is effected owing to the mass ornozzle meeting the mould.

In the cylindrical body 3 is inserted a pipe l which is provided infront with an enlargement l. The annular space 6 between the pipe I andthe cylindrical body 3 forms the passagethrough which the mass is iedunder high pressure by a plunger which is moved in a cylinder' in whichthe mass in contained. 'The enlargement i is provided with a passage 1which is in communication with the annular space l. In the cylindricalbody I' is screwed the nozzle head l in the front of which isinsertedthe nozzle 9. Be-

tween the. nozzle 9 and the enlargement l there is a space lIlin whichthe cylinder Il, which is iixed in the pipe l, is situated. Thiscylinder has a recess i2 in which a spring I3 is disposed.

The nozzle 9 is axially displaceable in the head parts shown in Figure 1during the casting, proc- In the form otconstruction according-to Fisl.For thisv purpose the nozzle is provided withpassage 28 which tapersconically towards the oriiice and from which transverse passages Ilextend. At the inner end of the neck 34 is xed the plate 31 of a platevalve, the seating surface Il of which is provided on the nozzle head 8.The inner end of the passage 2l is closed by a. plug 38 against whichthe spring Il bears. v

The transverse passages -36 are so arranged that, when the nozzle 9isseparated from the mould I, their outer oriiices are covered by thesurface of the aperture 35 in which the nozzle Figure 1 is alongitudinal section through one 56 head 8 is guided. `Under the actionoi' the spring I! the plate 31 is pressed against its seating Il.Therefore the nozzle passage 2831s closed at `two places to the passageill through which lthe mass to be cast isied.

When the cylinder containing the mass is moved forward, the nozzle 9 isbrought into contact with the mould, and is pressed back into theposition shown in Figure 6. It thereby opens the plate valve 31 and thetransverse passages 36 are placed in communication with the space I0.The mass can therefore pass through the passages 8 and 'l the space I0and the transverse passages 3i to the nozzle passage 28. When thecylinder containing the mass is withdrawn the parts again move backunder the action of the spring Il into the position illustrated inFigure 5 in which the passage through which the mass p is fed is doublyclosed to the nozzle passage 28. Therefore only the very small quantityof mass which is contained in the nozzle passage Il can escape.

The spring which acts on the closure member can, if necessary, also bearranged outside the passage through which the mass is supplied.

I claim:

1. The cylinder of a die-casting machine for plastic materials providedwith a closure member for its nozzle which comprises, in combimtion,- acylindrical body. a hollow nozzle head attached to said body, said bodyand said head being provided with connecting passages for the movementoi.' plastic material from the-one into the other during casting, anaxially displaceable nozzle inserted into the frontend oi.' said headand extending with its rear portion intothe hollow space of said head,said nozzle being provided with a central passage closed at'said rearpor. tion and with transverse passages extending Vfrom the centralpassage, a plug-like element attached to said cylindrical body withinsaid hollow space and arranged therein opposite to and co-axially withsaid nozzle, and afcompressible spring disposed on the one end of saidelement and bearing against the closed inner end ot said nozzle, saidtransverse passages extending through the nozzle in relation to thenozzle head so that they communicate with the hollow space of said headwhen Athe nozzle is displaced rearwardly in the front end of the headagainst the action of the spring, but are shut ci! from communicationwhen the action oi the spring forwardly displacesthe nomle in said head.

2. The cylinder of the die-casting machine in accordance with claim 1 inwhich a seating sur.

face is provided in theinner front end oi' the nozzleI head, and a plateis iixed to the rear portion of the nozzle, said surface and said plateco-acting tofunction as a valve which is open when the nozzle isdisplaced against the action o! the spring, hut closes when the actionof the spring forwardly advances the nozzle in the head.

PAUL BEYERLEIN.

